DEVELOPMENT OF ANTI-INFLAMMATORY OIL MICROSPHERE AND EVALUATING THE ACTIVITY IN VITRO AND IN VIVO

Objective: Citrus maxima (Burm). Merr. (C. maxima) peel oil is traditionally used to relieve stress. Its antimicrobial, cardioprotective, hepatoprotective, and anti-inflammatory properties make it a versatile remedy. C. maxima hold immense potential in modern therapeutic applications. This study aimed to formulate and evaluate Citrus maxima microspheres for in vitro and in vivo anti-inflammatory activity.

Methods: The present study was carried out using Citrus maxima peel oil extracted and GC-MS (Gas Chromatography-Mass Spectroscopy) was performed for complete chemical profiling. Microspheres were prepared using chitosan polymer with an emulsion chemical crosslinking approach and evaluated using SEM (Scanning Electron Microscopy), infrared spectroscopy, thermogravimetric assay, XRD (X-ray Diffraction), etc. An in vitro assay was performed using the inhibition of albumin denaturation assay and the membrane stabilisation method. In vivo anti-inflammatory activity was assessed using Carrageenan-Induced paw edema.

Results: GC-MS of Citrus maxima peel oil identified limonene (69.98%), beta-myrcene (6.23%), auraptene, alpha-pinene, and linalool as significant constituents. Formulation 1 (F1) showed the highest yield (79.28%), drug loading (84.28%), and encapsulation efficiency (78.32%) and also the highest swelling index (900.2%). The in vitro release of up to 72.03% in 8 h from F1 followed Higuchi kinetics (R² = 0.9859), suggesting diffusion-controlled release. Anti-inflammatory bioassays showed significant inhibition of protein denaturation and membrane lysis comparable to Diclofenac. In vivo, F1 microspheres at 400 mg/kg suppressed paw edema by 88.24%, approaching the activity of indomethacin (94.12%), establishing enhanced and sustained anti-inflammatory activity.

Conclusion: Citrus maxima oil-loaded microspheres exhibited enhanced anti-inflammatory activity in both in vitro and in vivo models. These findings suggest promising implications for the development of plant-based, biopolymer-encapsulated formulations as effective natural anti-inflammatory therapeutics.